The principles and practice of antenna design and operation is well known, and summarized, for example, in [T. A. Milligan, Modern Antenna Design, McGraw-Hill (1985).]. Antenna designs include many forms. For example, antenna designs include simple dipole/gap antennas, log-periodic antennas, and Yagi antennas. Further, phased arrays of antenna elements are widely used in Radar for beam parameter control and steering. One of the simplest antennas is a dipole with a gap. Electric field strengths in a correctly designed gap can exceed 103 to 104 of the incident field strength.
In a typical antenna, usually some kind of gap antenna (or array of such antennas) is constructed from metal, whose characteristic size is on the order of half the radio frequency (RF) wavelength. At 100 GHz the wavelength is 3 mm, at 10 GHz it is 30 mm and at 1 GHz it is 300 mm (˜1 foot), which RF requires an antenna with a characteristic size, which is physically large compared to many applications, such as for satellite applications. Such a large scale is required for the use of metal antennas.
Jain et al. discuss the possibility of a semiconductor antenna [F. C. Jain et al, ‘Semiconductor Antenna: A New Device in Millimeter- and Submillimeter-Wave Integrated Circuits’, IEEE Trans. Microwave Theory and Techniques, MTT-32, p. 204, (1984).], and briefly speculate on the concept of monolithic antenna to integrated circuit (IC) integration, perhaps on sapphire. Jain et al., however, do not mention plasmons, nor do they mention resonantly coupled arrays of semiconductor antennas for signal enhancement.
Semiconductor antennas comprising a doped semiconductor material have been demonstrated, for example, in U.S. Patent Application Publications 2011/0170103 and 2012/0074323 to Rivas et al. In particular, Rivas et al. disclose a semiconductor antenna made of doped InSb, and operated in the THz region. Such a semiconductor antenna operating in the THz region, however, is of little use to RF communication engineers as the signals in THz region are heavily absorbed in the atmosphere by water droplets. Instead such a THz region antenna is appropriate for use as a biosensor, as biological material changes affect local refractive index and thus affect antenna resonances. The antennas in Rivas et al are not mentioned as appropriate for use in communications purposes, nor is there any mention of sub THz operations.